褐煤深度脱水的实验研究

Experimental investigation on deep dewatering of lignite

针对褐煤低温烟气干燥技术脱水幅度难以提高,发热量增加不多等问题,提出了低温干燥与深度脱水的联合工艺。研究了不同干燥温度、干燥时间和煤样粒度对褐煤深度脱水效果的影响,结果表明:褐煤深度脱水适宜的干燥温度为500～800℃,较为适宜的干燥时间为80 s左右,当粒度小于50 mm时,干燥产物发热量随粒度变化不大。最后提出了褐煤深度脱水最佳工艺条件和参数,即当预干燥煤的Mar约为18%,煤样粒度为-50 mm,干燥温度为700℃,干燥时间为80 s时,深度脱水产物的Mar为8%,Vdaf在46%左右,折算Qnet,ar约为21 kJ/g。褐煤深度脱水促进了褐煤发热量的进一步提高,实现了褐煤资源的增值,研究结果为褐煤低温干燥与深度脱水联合工艺技术方案的确定奠定了基础。

Low temperature gas drying technology has several shortcomings during drying lignite, sucn as Its naru to increase the amount of dehydration, meanwhile, the calorific capacity of drying products also increases little. In order to address those shortcomings, provide a new techno]ogy which combines low temperature drying technology with deep dewatering technology. Investigate the influence of drying temperature, drying time and particle size of coal samples on dehydration effects. The results show that the proper temperature ranges from 500 °C to 800 °C, the appropriate drying time is about 80 seconds. When the particle size is below 50 ram, the calorific capacity of drying products varies little with the change of particle size. At last, determine the best technological condition and parameters of this new technology for lignite, that is, when the total moisture of predrying coal is about 18%, particle size of coal samples is below 50 mm, drying temperature is 700°C, drying time is 80 seconds, the mass fraction of total moisture of deep dewatering lignite could reach 8%, volatile matter is about 46%, converting calorific capacity is 21 kJ/g. This new technology further improves the calorific capacity of lignite, which indirectly improves the lignite＇s value. This study provides a basis for the determination of technical proposal which combines low temperature drying technology with deep dewatering technology.